<!doctype html>
<html lang="zh">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>DOM1</title>
</head>
<body>
<div id="test">
    <div class="red">hi</div>
    <div>hello</div>
    <div class="red">nihao</div>
</div>
<script src="dom.js"></script>
<script src="main.js"></script>
</body>
</html>